 /* 重置样式 */
 * {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
 }

 body {
     font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
     line-height: 1.6;
     background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
     min-height: 100vh;
     padding: 20px;
 }

 .container {
     max-width: 1200px;
     margin: 0 auto;
     background: white;
     border-radius: 15px;
     box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
     overflow: hidden;
 }

 /* 导航栏基础样式 */
 .navbar {
     display: flex;
     justify-content: space-between;
     align-items: center;
     padding: 1rem 2rem;
     background: #fff;
     box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
     position: relative;
 }

 .nav-brand {
     font-size: 1.8rem;
     font-weight: bold;
     color: #333;
     text-decoration: none;
     display: flex;
     align-items: center;
     gap: 10px;
 }

 .nav-brand::before {
     content: "🚀";
     font-size: 1.5rem;
 }

 /* 导航菜单 */
 .nav-menu {
     display: none;
     flex-direction: column;
     gap: 0;
     position: absolute;
     top: 100%;
     left: 0;
     right: 0;
     background: white;
     padding: 0;
     box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
     border-radius: 0 0 15px 15px;
     overflow: hidden;
     z-index: 1000;
     transform: translateY(-10px);
     opacity: 0;
     transition: all 0.3s ease;
 }

 .nav-menu.active {
     transform: translateY(0);
     opacity: 1;
 }

 .nav-menu li {
     list-style: none;
     border-bottom: 1px solid #f0f0f0;
 }

 .nav-menu li:last-child {
     border-bottom: none;
 }

 .nav-menu a {
     display: block;
     padding: 1rem 2rem;
     color: #333;
     text-decoration: none;
     transition: all 0.3s ease;
     font-weight: 500;
 }

 .nav-menu a:hover {
     background: #667eea;
     color: white;
     padding-left: 2.5rem;
 }

 .nav-menu a::before {
     content: "› ";
     font-weight: bold;
     margin-right: 5px;
     transition: all 0.3s ease;
 }

 .nav-menu a:hover::before {
     transform: translateX(5px);
     color: white;
 }

 /* 汉堡菜单 */
 .nav-toggle {
     display: flex;
     flex-direction: column;
     gap: 4px;
     background: none;
     border: 2px solid #f0f0f0;
     border-radius: 8px;
     cursor: pointer;
     padding: 0.5rem;
     transition: all 0.3s ease;
 }

 .nav-toggle:hover {
     border-color: #667eea;
     background: #f8f9ff;
 }

 .nav-toggle span {
     width: 25px;
     height: 3px;
     background: #333;
     transition: all 0.3s ease;
     border-radius: 2px;
 }

 /* 汉堡菜单动画 */
 .nav-toggle.active span:nth-child(1) {
     transform: rotate(45deg) translate(6px, 6px);
 }

 .nav-toggle.active span:nth-child(2) {
     opacity: 0;
 }

 .nav-toggle.active span:nth-child(3) {
     transform: rotate(-45deg) translate(6px, -6px);
 }

 /* 中等屏幕 (平板) */
 @media (min-width: 768px) {
     .nav-toggle {
         display: none;
     }

     .nav-menu {
         display: flex !important;
         position: static;
         flex-direction: row;
         box-shadow: none;
         padding: 0;
         transform: none !important;
         opacity: 1 !important;
         gap: 0.5rem;
         background: transparent;
         border-radius: 0;
     }

     .nav-menu li {
         border-bottom: none;
     }

     .nav-menu a {
         padding: 0.5rem 1rem;
         border-radius: 8px;
         position: relative;
         overflow: hidden;
     }

     .nav-menu a::before {
         display: none;
     }

     .nav-menu a::after {
         content: '';
         position: absolute;
         bottom: 0;
         left: 50%;
         width: 0;
         height: 2px;
         background: #667eea;
         transition: all 0.3s ease;
         transform: translateX(-50%);
     }

     .nav-menu a:hover {
         background: #f8f9ff;
         color: #667eea;
         padding-left: 1rem;
     }

     .nav-menu a:hover::after {
         width: 80%;
     }
 }

 /* 大屏幕 (桌面) */
 @media (min-width: 1024px) {
     .navbar {
         padding: 1.5rem 3rem;
     }

     .nav-menu {
         gap: 1rem;
     }

     .nav-menu a {
         padding: 0.75rem 1.5rem;
         font-size: 1.1rem;
     }
 }

 /* 内容区域 */
 .content {
     padding: 3rem 2rem;
     text-align: center;
 }

 .content h1 {
     color: #333;
     margin-bottom: 1rem;
     font-size: 2.5rem;
 }

 .content p {
     color: #666;
     font-size: 1.2rem;
     max-width: 600px;
     margin: 0 auto 2rem;
 }

 .demo-grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
     gap: 2rem;
     margin-top: 3rem;
 }

 .demo-card {
     background: #f8f9ff;
     padding: 2rem;
     border-radius: 12px;
     box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
     transition: transform 0.3s ease;
 }

 .demo-card:hover {
     transform: translateY(-5px);
 }

 .demo-card h3 {
     color: #333;
     margin-bottom: 1rem;
 }

 .demo-card p {
     color: #666;
     font-size: 1rem;
 }

 /* 屏幕尺寸指示器 */
 .screen-size {
     position: fixed;
     bottom: 20px;
     right: 20px;
     background: rgba(0, 0, 0, 0.8);
     color: white;
     padding: 10px 15px;
     border-radius: 20px;
     font-size: 0.9rem;
     z-index: 1000;
 }

 /* 代码展示区域 */
 .code-section {
     background: #1e1e1e;
     color: #d4d4d4;
     padding: 2rem;
     margin: 2rem 0;
     border-radius: 10px;
     overflow-x: auto;
     font-family: 'Courier New', monospace;
 }

 .code-section h3 {
     color: #fff;
     margin-bottom: 1rem;
 }